Gripping device



P 22, 1953 D. w. WASSHEM 4 GRIPPING DEVICE Filed Feb. 25, 1952 PatentedSept. 22, 1953 GRIPPING DEVICE Dore Waldemar Wasshem, Norrkoping, SwedenApplication February 25, 1952, Serial No. 273,164 In Sweden February 13,1952 Claims.

The present invention relates to gripping devices, such as vises orchucks, the jaws of which are supported by tubes in telescopicengagement with each other and in which means are provided forinterlocking said tubes and tightening them with relation to each other.More particularly, the invention relates to gripping devices of saidtype in which the locking and tightening means comprise a sleeve havinga wedge-shaped slit and a wedge member in engagement with said slit, thelocking and tightening operation being effected by a relative axialdisplacement of said elements with relation to each other.

An object of the invention is to provide a gripping device of this typewhich allows a rapid operation in gripping and releasing work piece.

A feature of the invention resides in the provision on the inner one oftwo telescopic tubes or on a member connected thereto of a helicalsurface for effecting said axial displacement by a rotary movement of acontrol element. To this end, said helical surface is engaged by thebottom end of the wedge member, so that a rotation of the elementcarrying the helical surface will effect or allow an axial displacementof the wedge member.

According to another feature of the invention the sleeve is shaped as astraight cylinder and bears at that end which merges with the widerportion of the wedge-shaped slit, against an axially stationaryshoulder, and is engaged at its opposite end by an axially resilientsupport.

A still further feature involves a sleeve comprising two semicylinders,or more than two members, separated by longitudinal slits and curved inconformity with the cylindrical inner surface of the outer tube.

The invention is illustrated in the accompanying drawing, in which:

Fig. 1 is a part sectional side elevation of a vise embodying theinvention;

Fig. 2 is an axial section on a larger scale of the right hand portionof Fig. 1 shown in side elevation therein;

Fig. 3 is a cross section on the line III-HI of Fig. 2;

Fig. 4 is a perspective view of part of the control element, and

Fig. 5 is a perspective view of the sleeve members.

The vise illustrated in the drawing comprises as main elements an outertubular member I adapted to be attached to a table (not shown) andprovided with a jaw 2, preferably formed integrally therewith, and aninner tubular member 3 slidable axially in the member I and prothetubular member 3 supporting the jaw 4 and carrying by its projecting enda nut 8 bearing against a ring 9 fitted in an enlargement of the. boreof the inner tubular member 3. The nut 8 as well as the end of the rodcarrying same are formed with a transverse bore for receiving a controllever ID for rotating the rod 1.

The opposite end of the rod I extends beyond the adjacent end of tube 3and is connected to a piston-like head II inside the outer tube I. Saidmember II is of a diameter approximately equal to the inner diameter ofthe outer tube so that it can be rotated therein. On its side facing therod 1 the head II is formed with a cylindrical projection I2 of asmaller diameter so that a shoulder I2 is formed on the head II aroundthe projection I2. The end surface of the projection I2 is helicallycut, as shown at I3, to serve as a guide surface for a wedge I4 having acorrespondingly helically cut base surface for cooperation with thehelical surface I3, as shown in Fig. 2.

Surrounding the cylindrical surface of the projection I2 are twosemicylindrical sleeve portions I5 and I6 which form together a sleevehaving a wedge-shaped slit for receiving the wedge I4. At 20, Fig. 2, isshown a, longitudinal extension of said slit, said extension being ofuniform width along its entire length. The semicylindrical sleeveportions I5, I6 engage by their peripheral surfaces the innercylindrical surface of the outer tube I. The end surfaces of the sleevemembers I5, I6 facing the head II is situated in a plane at right anglesto the axial direction of the sleeve members and bear against theshoulder of head II. The end surfaces of the sleeve members I5, I6remote from the head I I is conically countersunk to receive thecorrespondingly conical end of a washer I! the conicity being such thatthe members I5 and I6 may be forced outwardly against the inner wall oftube I when the washer I1 is forced axially thereagainst. The washer I1is under the action of a helical spring I8 inserted between the washerand a shoulder formed in the inner tube II.

The operation is as follows:

In the released, or normal, state of the locking and tightening device,the jaw 4 may be easily moved axially by operating the lever I so as toallow the insertion of a work piece between the jaws and then pushingthe jaw 4 by hand until it holds the work piece with a moderate pressureagainst the stationary jaw 2. This means saving of time, as comparedwith the operation of usual vises in which the movable jaw is moved by ascrewing operation. The work piece having thus been initially gripped bythe jaws, the rod 1 is rotated by means of the lever ID in such adirection as to cause the helical surface [3 to displace the wedgemember I4 in the direction away from the head II. This may be donebecause of the fact that the sleeve members l5, 16 are held infrictional engagement with the inner surface of tube I under the actionof spring 1%, via: washer I 1, so that the members I5, [6' and thusalsothe wedge M are prevented from rotating with the head H. Bysaidlongitudinal movement of the wedge l4; (to the left in Fig. 2) thesleeve members IE, IS; are tightened against the said inner cylindricalsurface of tube 1 and lockedv thereto. Since the tube, I is stationary,the sleevememb'ersv l5, l and the wedge 14 are also held stationary. Itis thus obvious that in the continued rota-tionof the rod '1 theobliquely cut base surface of the wedge It will act as a stationaryguideway for the helical surface l3 causing the head H with rod 1 andinner tube 3 with jaw 4 to move to the right in Fig. 2, that is to say,the jaw 411s drawn nearer to the sta tionary jaw 2. This, means atightening of the jaws upon the: work piece.

In the example shown, the tightening effect may, as a maximum,correspond to a rotation of the rod. through a complete revolution, andthe maximumtightening displacement may be equal to the distance betweenthe inlet and outlet ends: of the helical surface it during onerevolution, that is to. say, equal tot-he distance l9. in Fig. 4, whichis quite sufficient in'pr-actice. As regards the-material commonly usedin work pieces only a fraction ofa revolution is required.

To release the workpiece thelev-er it; is rotated inathe, oppositedirection, thereby removing the pressure of: the surface [3 on thewedge. The pressure of the wedge on the sleeve members into-twoseparateparts'as-well as to the conical shape of thecoeng-aging surfaces of thewasher- H and the sleeve members. Said sleeve members arealwaysmaintained in'engagement withthe innersurfaceof the tube l and theuse of: separate. sleeve members brings the advantage with it that thesleeve members may readily stick-:to. the inner surface of the tube upona ro-' t'ation oftherod I.

I-claim:

1. A gripping mechanism comprising a pair of'jaws, an inner and an outertubein'telescopic engagement witheach' other forsupporting saidjaws, alocking and tightening device being pro-' 4 vided between said tubes andcomprising a sleeve expansible into contact with said outer tube andhaving a wedge-shaped slit and a wedge in engagement with said slit,said sleeve and said wedge being relatively movable longitudinally ofthe outer tube, said inner tube having a rotatable control devicecomprising a central rod rotatably mounted in the inner tube, apiston-like head on said rod mounted in the outer tube, a helicalsurface being provided on one side of a portion of said head forengaging said wedge so as to effect an axial displacement thereof uponrotation of said control device, said head portion having a smallerdiameter than the head proper to provide an annular shoulder at the baseof said portion.

2. A gripping mechanism comprising a pair of jaws; an inner and an outertube in telescopic engagement with each other for supporting said jaws,a locking and tightening device, being provided between said tubes,andcomprising a sleeve expansible into contact with said outer tube andhaving a wedge-shaped slit and a wedge in engagement with said slit,said sleeve and said wedge being relatively movable longitudinally ofthe outer tube, said inner tube having a rotatable control devicecomprising a central rod rotatably mounted in the inner tube, apiston-like head on said rod mounted in the outer tube, a helicalsurface being provided on, one side of a portion; or"- said' head forengaging said wedge so as to effect an axial displacement thereof uponrotation of said control device, said head portion having a smallerdiameter than the head properto provide an annular shoulder at the baseof said portion for engagement with one end of the expansible sleeve,the other end ofsaid sleeve being under the action of a spring loadtending to maintain said engagement.

3, A gripping device as claimed in claim 2; in which the expansiblesleeve comprises at least twolongitudinally extending members, capableof separately engaging the inner cylindrical surface of the outer tubeby their entireouter surface.

4,. A gripping device as claimed inclaim 2, in which the spring loadcomprises'a helical spring and a washer acted on-by said spring fortransmitting the spring action to the end of the expansible sleeveremote-fromthe annular shoulder ofthe control device.

5. A gripping device as claimed in claim 2, in which the spring loadcomprises a helical spring and a washer acted on by said spring fortransmitting the spring action to the end of the expansible sleeveremote from the annular shoulderof' the control device, the end of thesleeve engaged by the washer being conically countersunk and the surfaceof the washer in engagement therewithbeing correspondingly conical.

DORE WAEDEM-AR W-A SSHEM.

References Cited in the file of this patent UNITED STATES PATENTS Numberi Name Date- 621,294 Culver Mar. 14, 1899 631,991 James et a1 Aug. 29,1899 1,155,027 Wright Sept; 28, 1915 2,599,222- Bergqvist l June 3, 1952FOREIGN PATENTS Number Country v Date 1 6 W e 1- Sep -'2. 1947'"

